trillebar
Dec6-10, 04:45 AM
I need someone to verify/falsify the following statement (from an untrusted source):
A parallel plate wave guide with perfectly conducting planes and vacuum between the plates is propagating a TE-mode. Assuming c is the speed of ligth, then the group velocity v_g satisfies: v_g > c.
I migth have mistaken, but I were to understand that group velocity = rate of information transfer. If this is the case, then the statement implies that the wave guide is transfering information faster than the speed of ligth, which is not possible!
Cheers!
EDIT: I finally found the answer in my el.mag. book, and it should of course be: v_g < c.
A parallel plate wave guide with perfectly conducting planes and vacuum between the plates is propagating a TE-mode. Assuming c is the speed of ligth, then the group velocity v_g satisfies: v_g > c.
I migth have mistaken, but I were to understand that group velocity = rate of information transfer. If this is the case, then the statement implies that the wave guide is transfering information faster than the speed of ligth, which is not possible!
Cheers!
EDIT: I finally found the answer in my el.mag. book, and it should of course be: v_g < c.